Assistant Professor of Otolaryngology - Head and Neck Surgery at the Stanford University Medical Center

Otolaryngology - Head & Neck Surgery Divisions

Bio

Bio

Dr. Vasu Divi specializes in the treatment of head and neck cancer, both as a cancer surgeon and a reconstructive surgeon. Dr. Divi has a special interest in high-risk and advanced skin cancers, oral cavity cancers, and osteoradionecrosis of the head and neck. He utilizes advanced 3D-modeling to customize reconstruction of the jaw following surgery for cancer or radiation injuries.

Links

Research & Scholarship

Clinical Trials

The purpose of this study is to characterize the blood supply at the base of the tongue and
within the tonsil region. We hypothesize that high-resolution Narrow Band Imaging (NBI) will
improve the diagnosis of oropharyngeal carcinoma (OPC). The goal is to provide the better
assessment of tumor and thus providing better preoperative expectations to patients with OPC
or tumor extent prior to radiation therapy.

Stanford is currently not accepting patients for this trial.For more information, please contact Priya Hegde, 650-723-0920.

This study is an open label, single institution, Phase 1 dose-escalation study to determine
the safety profile of cetuximab-IRDye800 used in subjects with head and neck squamous cell
carcinoma (HNSCC) that undergo surgery with curative intent. Participants will be given a
dose of an approved head and neck cancer drug (Cetuximab) along with an investigational study
drug called Cetuximab-IRDye800. Cetuximab-IRDye800 is a drug that is given prior to surgery
that attaches to cancer cells and appears to make them visible to the doctor when he uses a
special camera during the operation. The investigators are evaluating whether or not the use
of the study drug along with the special camera will better identify the cancer while
patients are in the operating room.

Stanford is currently not accepting patients for this trial.For more information, please contact Alifia Hasan, 650-721-4088.

Phase I trial to evaluate the safety of escalating dose levels of conjugated
panitumumab-IRDye800 in subjects with head and neck squamous cell carcinoma (HNSCC) that
undergo surgery with curative intent.

Publications

All Publications

Abstract

The importance of providing quality care over quantity of care, and its positive effects on health care expenditure and health, has motivated a transition toward value-based payments. The Centers for Medicare and Medicaid Services and private payers are establishing programs linking financial incentives and penalties to adherence to quality measures. As payment models based on quality measures are transitioned into practice, it is beneficial to identify current quality measures that address breast reconstruction surgery as well as understand gaps to inform future quality measure development.We performed a systematic review of quality measures for breast reconstruction surgery by searching quality measure databases, professional society clinical practice guidelines, and the literature. Measures were categorized as structure, process, or outcome according to the Donabedian domains of quality.We identified a total of 27 measures applicable to breast reconstruction: 5 candidate quality measures specifically for breast reconstruction surgery and 22 quality measures that relate broadly to surgery. Of the breast reconstruction candidate measures, 3 addressed processes and 2 addressed outcomes. Seventeen of the general quality measures were process measures and 5 were outcome measures. We did not identify any structural measures.Currently, an overrepresentation of process measures exists, which addresses breast reconstruction surgery. There is a limited number of candidate measures that specifically address breast reconstruction. Quality measure development efforts on underrepresented domains, such as structure and outcome, and stewarding the measure development process for candidate quality measures can ensure breast reconstruction surgery is appropriately evaluated in value-based payment models.

Abstract

Multiple disease processes, including neoplasia, trauma, and medication side-effects, necessitate segmental resection and subsequent reconstruction of the mandible. As surgical techniques have advanced, several technologies have been developed with the potential to significantly transform a surgeon's approach to the restoration of mandibular continuity. The purpose of this review is to highlight many of these relatively newer tools and discuss their evolving role in mandibular reconstruction.Several contemporary studies have documented the application of different approaches and modifications to mandibular reconstruction - including computer-aided design or computer-aided modeling, contemporary plating systems, osseointegrated implants, and various modifications to existing osseocutaneous free tissue transfer options - and have reported relatively high success rates.In discussing these reports, we present a survey of current and developing technologies in the field of mandibular reconstruction and aim to provide sufficient context for the gradual integration of these techniques into practice.

Abstract

Advanced head and neck cancer (HNC) is a complex group of diseases that requires the input and coordination of multiple providers. While there are general guidelines for treatment, there is also considerable variation in how patients are treated, and how long they survive after treatment. It is unclear how the treatment variations relate to treatment costs and survival.We identified 3678 Medicare patients with advanced HNC treated in 12 US regions between 2004 and 2009 using the linked database containing Medicare and Surveillance Epidemiology and End Results (SEER) data. We calculated average cost per patient during the period three months before to 12months after diagnosis for each region. Costs included inpatient hospital, outpatient, physician, and durable medical equipment charges. We also calculated three-year overall survival for each of the regions.The mean cost-per-patient varied substantially among the regions, ranging from $51,857 for Utah to $82,181 for Detroit. Utah incurred the lowest total costs within one year of advanced HNC diagnosis ($51,857 per patient, 95% CI $42,285-$61,429), whereas Detroit had the highest costs ($82,181 per patient, 95% CI $74,752-$89,610). Overall survival also varied among the regions, ranging from 45months in Kentucky to 58months in Washington. There was little correlation between expenditures and length of survival, with correlation coefficient of 0.0088.Despite significant variation in both expenditures and survival among the regions, we found no correlation between costs and mean survival time, suggesting that more costly care did not lead to improved outcomes.

Abstract

Definitive assessment of primary site margin status following resection of head and neck cancer is necessary for prognostication, treatment determination and qualification for clinical trials. This retrospective analysis determined how often an independent reviewer can assess primary tumor margin status of head and neck cancer resections based on review of the pathology report, surgical operative report, and first follow-up note alone.We extracted from the electronic medical record pathology reports, operative reports, and follow-up notes from head and neck cancer resections performed at Stanford Hospital. We classified margin status as definitive or not. We labeled any pathology report clearly indicating a positive, negative, or close (<5mm) margin as definitive. For each non-definitive pathology report, we reviewed the operative report and then the first follow-up note in an attempt to clarify margin status. We also looked for associations between non-definitive status and surgeon, year, and primary site.743 unique cases of head and neck cancer resection were extracted. We discarded 255 as non-head and neck cancer cases, or cases that did not involve a definitive resection of a primary tumor site. We could not definitively establish margin status in 20% of resections by independent review of the medical record. There was no correlation between margin determination and surgeon, site, or year of surgery.A substantial fraction (20%) of primary site surgical margins could not be definitively determined via independent EMR review. This could have implications for subsequent patient care decisions and clinical trial options.

Regional variation in head and neck cancer mortality: Role of patient and hospital characteristicsHEAD AND NECK-JOURNAL FOR THE SCIENCES AND SPECIALTIES OF THE HEAD AND NECKDivi, V., Ma, Y., Rhoads, K. F.2016; 38: E1896-E1902

Abstract

Oroantral fistula (OAF) is a pathologic, epithelialized communication between the oral cavity and the maxillary sinus. OAF most commonly results from posterior maxillary tooth or molar extraction owing to proximity of the dental roots to the maxillary antrum and the thinness of the adjacent antral floor. It also can arise secondary to implant and orthognathic surgeries, cyst and tumor removal, dental infection, trauma, or as a sequela of radiation therapy. Communications larger than 5 mm are less likely to heal spontaneously and can epithelialize, forming an OAF. When locoregional flaps and grafts are not ideal or have failed, but primary OAF closure is mandated, surgical options are unclear. This report describes a novel method for autologous tissue flap coverage from the nasal septum, pedicled off the posterior septal artery, for successful extension to, and closure of, OAFs.

Abstract

Electronic data collection is increasingly used for quality of life (QOL) assessments in the field of oncology. It is important to assess the feasibility of these new data capture technologies.Patients at our institution who were 18years or older with a pathological diagnosis of head and neck cancer were prospectively enrolled. Each patient completed two questionnaires [EORTC-QLQ-C30 and EORTC-QLQ-H&N35] administered on a touch-screen tablet device (iPad?) at initial consult, during treatment, at the completion of treatment and at each subsequent follow up visit for one year after treatment.A total of 50 patients were included in this study. Although all patients completed the surveys at the initial consult, 86% of initially enrolled patients completed surveys at the end of radiation treatment, and 48% of initially enrolled patients completed surveys by the fourth follow-up visit. Average time to complete the survey for all patients over all time points was 9.8min (standard deviation 6.1). Age as a continuous variable was significantly associated with time for survey completion (p<0.001), with older age associated with longer survey completion times.QOL assessment using tablet devices in head and neck cancer patients is feasible, but may be more challenging in elderly patients. Patients ?70years old may benefit from more assistance with electronic forms and should be allotted more time for completing tablet-based QOL surveys.

Abstract

Tumor-initiating cells (TICs) in squamous cell carcinoma of the head and neck (SCCHN) are best characterized by their surface expression of CD44. Although there is great interest in identifying strategies to target this population, no marker of these cells has been found to be functionally active. Here, we examined the expression of the purported marker of normal human oral epithelial stem cells, CD271. We show that CD271 expression is restricted to a subset of the CD44+ cells. Using xenograft assays, we show that the CD44+CD271+ subpopulation contains the most tumorigenic cells. Loss of CD271 function results in a block in the G2-M phase of the cell cycle and a profound negative impact on the capacity of these cells to initiate tumor formation in vivo. Incubation with recombinant NGF results in enhanced phosphorylation of Erk, providing additional evidence that CD271 is functionally active. Finally, incubation of SCCHN cells with antibody to CD271 results in decreased Erk phosphorylation and decreased tumor formation in vivo. Thus, our data are the first to demonstrate that CD271 more specifically identifies the TIC subpopulation within the CD44+ compartment in SCCHN and that this receptor is a functionally active and targetable molecule.

Abstract

Cancer stem cells possess the qualities of self-renewal, tumorigenesis and the ability to recapitulate a heterogeneous tumor. Our group was the first to isolate head and neck squamous cell carcinoma (HNSCC) stem cells using the cell surface marker CD44. CD44 is a trans-membrane glycoprotein with a multitude of key-functions that regulate cancer cell proliferation and metastasis. The variety of CD44 functions is due to tissue-specific patterns of glycosylation of the extracellular portion, and to the multiple protein isoforms (CD44 variants, CD44v) generated by alternative splicing. This study investigates the expression pattern of CD44 variants in HNSCC. Ten cell lines from the most common HNSCC locations and representative of various clinical outcomes were assayed by quantitative realtime PCR, flow cytometry and immunofluorescence comparatively with normal oral keratinocytes. The CD44 v4 and v6 were exclusively abundant in HNSCC while the isoform v1,2 was expressed in normal oral keratinocytes. Of interest, the highest level of CD44v6 expression was detected in advanced metastatic HNSCC, suggesting a link between CD44v6 expression and HNSCC metastasis, while the highest CD44v4 was detected in a stage IV HNSCC refractory to chemotherapy which developed recurrence. Oral-derived HNSCC expressed the highest CD44v4 and v6, and levels corresponded with staging, showing also an increasing tendency with recurrence and metastasis. CD44v were detected predominantly in smaller cells (a characteristic that has been associated with stem cell properties) or cells with mesenchymal morphology (a characteristic that has been associated with the migratory and invasive potential of epithelial tumor cells), suggesting that CD44v differential expression in HNSCC may be representative of the morphological changes inherent during tumor progression towards a more aggressive potential, and thus contributing to the individual tumor biology. The mechanism of CD44 variant involvement in HNSCC progression and metastasis is under investigation.

Abstract

The long-term outcome of patients with mucoepidermoid carcinoma is poor. Limited availability of cell lines and lack of xenograft models is considered a major barrier to improved mechanistic understanding of this disease and development of effective therapies.To generate and characterize human mucoepidermoid carcinoma cell lines and xenograft models suitable for mechanistic and translational studies.Five human mucoepidermoid carcinoma specimens were available for generation of cell lines. Cell line tumorigenic potential was assessed by transplantation and serial in vivo passaging in immunodeficient mice, and cell line authenticity verified by short tandem repeat (STR) profiling.A unique pair of mucoepidermoid carcinoma cell lines was established from a local recurrence (UM-HMC-3A) and from the metastatic lymph node (UM-HMC-3B) of the same patient, 4years after surgical removal of the primary tumor. These cell lines retained epithelial-like morphology through 100 passages in vitro, contain the Crtc1-Maml2 fusion oncogene (characteristic of mucoepidermoid carcinomas), and express the prototypic target of this fusion (NR4A2). Both cell lines generated xenograft tumors when transplanted into immunodeficient mice. Notably, the xenografts exhibited histological features and Periodic Acid Schiff (PAS) staining patterns that closely resembled those found in human tumors. STR profiling confirmed the origin and authenticity of these cell lines.These data demonstrate the generation and characterization of a pair of tumorigenic salivary mucoepidermoid carcinoma cell lines representative of recurrence and lymph node metastasis. Such models are useful for mechanistic and translational studies that might contribute to the discovery of new therapies for mucoepidermoid carcinoma.

Transoral robotic biopsy of the tongue base: A novel paradigm in the evaluation of unknown primary tumors of the head and neckHEAD AND NECK-JOURNAL FOR THE SCIENCES AND SPECIALTIES OF THE HEAD AND NECKAbuzeid, W. M., Bradford, C. R., Divi, V.2013; 35 (4): E126-E130

Abstract

Squamous cell carcinoma of the head and neck can present as a cervical metastasis from an unknown primary site. The standard diagnostic workup includes panendoscopy and directed biopsies but this will fail to identify a portion of unknown primary tumors.Herein, we present a case report of a male patient with an unknown primary tumor in which the da Vinci surgical robot was used to evaluate the tongue base.Clinical evaluation, imaging, and panendoscopy with directed biopsies failed to detect the primary tumor site. Robot-assisted biopsy of a broad area of the tongue base, incorporating submucosal tissue, identified the primary tumor with minimal postoperative morbidity.Failure to localize an unknown primary tumor often results in widespread irradiation of the upper aerodigestive tract, inducing significant morbidity. Robot-assisted biopsies of the tongue base may identify unknown primaries that would otherwise have been missed through standard directed biopsy techniques.

Abstract

To determine if the various imaging modalities for distant metastasis (DM) diagnosis alters life expectancy in head and neck squamous cell carcinoma (HNSCC).Retrospective.One hundred seventy patients (mean age, 59.1 years; male:female, 135:35) with HNSCC who developed DM were reviewed. The main outcome measures were the method of DM diagnosis and time from DM diagnosis to death while controlling for clinical parameters (age, gender, tobacco status, primary tumor site, initial TNM classification, number and site of DM, administration of palliative chemotherapy).Tumor subsites were: 40 oral cavity, 75 oropharynx, 36 larynx, 10 hypopharynx, one nasopharynx, and eight unknown primary. Of the patients, 16.5% (28/170) had distant metastasis at presentation; the remaining 142 patients were diagnosed with DM at a median of 324 days from diagnosis. Although patients diagnosed with DM by positron-emission tomography (PET) scan were more likely to have multiple DM sites (P = .0001), there were no differences in life expectancy in patients who were diagnosed with or without PET scan (median, 185 vs. 165 days, P = .833). There were no differences in life expectancy based on age, gender, site of primary tumor, or number/site of DM. The use of palliative chemotherapy resulted in a significantly longer life expectancy (median, 285 vs. 70 days; P = .001).Although a PET scan is more likely to diagnose multiple DM sites, there was no difference in life expectancy based on imaging modality. Patients who are symptomatic from their distant metastasis have a worse life expectancy, and palliative chemotherapy was able to increase life expectancy, even in patients who were symptomatic from the distant metastasis.

Abstract

Facial nerve paralysis can occasionally result from the treatment of head and neck cancer. The treatment of paralysis is patient specific, and requires an assessment of the remaining nerve segments, musculature, functional deficits, anticipated recovery, and patient factors. When feasible, reinnervation of the remaining musculature can provide the most natural outcome. However, the complex and topographic nature of facial innervation often prevents complete and meaningful movement. In these instances, a wide variety of procedures can be used to combat the functional and cosmetic sequella of facial paralysis.

Abstract

The authors examined the feasibility and advantages of primary tracheoesophageal puncture (TEP) with intraoperative placement of the voice prosthesis for patients undergoing laryngopharyngectomy requiring free tissue reconstruction and salivary bypass tube placement. Six patients were identified; 4 underwent total laryngopharyngectomy, and 2 underwent total laryngectomy with partial pharyngectomy. All 6 required free tissue reconstruction, and a salivary bypass tube was placed in all cases. All patients had a 20F Indwelling Blom-Singer prosthesis (InHealth Technologies, Carpinteria, California) placed. No complications were noted with intraoperative prosthesis placement. No prostheses were dislodged in the postoperative period. At 6 months, 4 patients available for evaluation had successful voice outcomes, and 3 were disease free. This study demonstrates the effectiveness of voice prosthesis placement at the time of primary TEP associated with free tissue reconstruction of a laryngopharyngeal defect with salivary bypass tube placement.

Abstract

to design in vitro and in vivo models of metastasis to study the behavior of cancer stem cells (CSCs) in head and neck squamous cell carcinoma (HNSCC).cells were sorted for CD44 expression using flow cytometry. Sorted cells were used in an in vitro invasion assay. For in vivo studies, CSCs and non-CSCs were injected into the tail veins of mice, and lungs were either harvested or imaged to evaluate for lesions.in vitro, CD44(high) cells were more motile but not more invasive than CD44(low) cells. In vivo, 8 of 17 mice injected with CD44(high) cells and 0 of 17 mice injected with CD44(low) cells developed lung lesions. Two of the lesions arose from CSCs from a primary tumor and 6 from CSCs from HNSCC cell lines.in vitro, CSCs do not have an increased ability to invade through basement membrane, but they migrate more efficiently through a porous barrier. In contrast, CSCs efficiently formed lung lesions in vivo, whereas non-CSCs did not give rise to any distant disease. This phenomenon could be due to the enhanced migratory capacity of CSCs, which may be more important than basement membrane degradation in vivo.

Abstract

For patients with advanced laryngeal cancer, a trial was designed to determine if chemotherapy alone, in patients achieving a complete histologic complete response after a single neoadjuvant cycle, was an effective treatment with less morbidity than concurrent chemoradiotherapy.Thirty-two patients with advanced laryngeal or hypopharyngeal cancer received 1 cycle of induction chemotherapy, and subsequent treatment was decided based on response.A histologic complete response was achieved in 4 patients and were treated with chemotherapy alone. All 4 patients' cancer relapsed in the neck and required surgery and postoperative radiotherapy (RT). Twenty-five patients were treated with concomitant chemoradiation. Three patients were treated with surgery. Overall survival and disease-specific survival at 3 years were 68% and 78%, respectively.Chemotherapy alone is not feasible for long-term control of regional disease in patients with advanced laryngeal cancer even when they achieve a histologic complete response at the primary site.

Abstract

The purpose of this study was to determine the diagnostic accuracy of using the retromandibular vein as seen on cross-sectional imaging to help differentiate superficial lobe from deep lobe tumors.Of the patients who had parotid neoplasms between January 1997 and July 2002, we were able to identify 44 patients with preoperative imaging studies that were available for evaluation. The films were reviewed by a single head and neck radiologist to determine whether the neoplasms involved the superficial, deep, or both lobes of the parotid gland (total). The lateral margin of the retromandibular vein was used as a marker for the facial nerve, since the nerve is not always visible on CT and MRI scans. The radiologist's findings were then compared with the findings during surgery. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of predicting the location of neoplasms were then calculated.For lesions in the superficial lobe, cross-sectional imaging was able to predict the location of the neoplasm with a sensitivity of 0.91 (95% CI, 0.70-0.98), specificity of 0.86 (95% CI, 0.63-0.96), PPV of 0.88 (95% CI, 0.67-0.97), and NPV of 0.90 (95% CI, 0.67-0.98). For lesions in both lobes (total), cross-sectional imaging was able to predict the location of the neoplasm with a sensitivity of 0.94 (95% CI, 0.68-0.99), specificity of 0.89 (95% CI, 0.71-0.97), PPV of 0.83 (95% CI, 0.58-0.96), and NPV of 0.96 (95% CI, 0.78-0.99).Use of the retromandibular vein as a marker for the facial nerve is a sensitive method for identifying the location of parotid gland neoplasms on cross-sectional imaging. This supports the accuracy of using preoperative imaging to detect the position of parotid neoplasms with respect to the facial nerve.